The present invention relates to information handling technology and improvements therein. More particularly, the subject invention relates to a new pacing algorithm for application in predictive dialers for use in telephone call centre operations.
The concept and evolution of pacing algorithms and the benefits that result from their use in predictive dialers in call centre activities have been appreciated for a number of years. Predictive dialers and pacing algorithms result in more efficient use of operators, agents or attendants, and more satisfied response from customers.
The functional integration of data processing systems with the information capabilities of telephone systems is becoming increasingly important in the enhancement and differentiation of today""s business solutions. The synergy that is provided by marrying telephones with computers opens nearly unlimited opportunities for companies to dramatically enhance service to their networked call centres. Inbound customer inquiries can be handled with increased speed and accuracy, significantly boosting customer satisfaction. Outbound customer applications such as tele-sales or tele-marketing can deliver more streamlined campaigns and increase the contact rate between agents and customers which can substantially increase revenue generation.
The CallPath(copyright) family of products available from International Business Machines Corporation (IBM) enable applications to link the data processing power of a computer with the telephony processing capabilities of telephone systems. The primary focus of these products is on inbound and outbound tele-servicing and tele-marketing application opportunities. Frequently these applications are concentrated within business in special departments known as call centres. Some examples of applications that the CallPath family of products can provide are order processing, claims inquiry, stock broker services, telephone sales, market research, help desk and dispatch, fund raising, lead generation, qualification and tracking. The enabled applications allow business to improve customer service, increase revenues, reduce telephone bills, improve employee productivity and promote overall competitiveness. These CallPath products and services enable communications between a computer and a telephone system so that an application on the computer can control and access telephony information. A variety of telephone applications can be automated including simple and repetitive requests, data/caller coordination, call handling, data collection, and outbound dialing. A better understanding of the CallPath family of products can be obtained from the publication IBM(copyright) CallPath General Information, publication #GC31-8529-0, available from IBM Corporation.
Predictive dialing is a state of the art technology for call centres. A predictive dialer automatically dials new customers before the call centre agents or attendants finish talking with their current customers. In this way, the predictive dialer is able to connect the new customers to the agents immediately after the agents become available. The core of the predictive dialing technology is the pacing algorithm which directs the telephone dialer as to when and how many customer telephone numbers it should dial. This decision is typically based mainly on the estimation of the agent availability. In addition, dial/hit ratio, dial delay and many other factors will have effects on the outcomes. The predictive dialer is able to recognize when a called telephone is engaged and a busy signal is received, when an answering machine responds to the called number, and when after a period of time the call is not answered. For an overview of the concept of predictive dialers, reference may be made to the book entitled xe2x80x9cPredictive Dialing Fundamentals-An Overview of Predictive Dialing Technologies, their Applications and Usagexe2x80x9d by Aleksander Szlam and Ken Thatcher, Flatiron Publishing Inc., New York, copyright 1996 Melita International Corporation.
The pacing algorithm which is the subject of this application, is based upon mathematical probability models and provides more accuracy in the dialing of outgoing telephone calls from a call centre than the use of presently known pacing algorithms. None of the existing algorithms take into account the multi-dimensional aspect of the probabilistic model as subsequently described in this application. The use of this algorithm could eliminate or at least minimize annoying calls from both the customer and the attendant""s point of view, when calls are made, and it is subsequently found that no one is at the other end of the connection.
The following references provide descriptions of representative examples of known prior art automated dialing systems and pacing algorithms employed therein:
U.S. Pat. No. 4,599,493 was granted Jul. 8, 1986 naming Ellis K. Cave as inventor, and is entitled xe2x80x9cMulti-Line Telephone Control Systemxe2x80x9d. The subject matter provides for a continuous sequence of telephone calls made by an automated telephone calling system which are forwarded to a plurality of operators. Each call is made to a designated telephone number and is dialed in sequence by a controller, and the line condition of the called number is detected. For each line that is answered, it is connected by the communication device to a non-occupied operator. A status message is sent to the host computer indicating the answered number and the operator involved, and relevant data is displayed to the operator by the computer. All of the designated telephone numbers are dialed in sequence and made available to operators, depending on the number of operators available and the number of customers who are waiting on hold.
U.S. Pat. No. 4,881,261 issued to Oliphant et al on Nov. 14, 1989, and is entitled xe2x80x9cMethod for Predictive Pacing of Calls in a Calling Systemxe2x80x9d. A predictive pacing algorithm instructs a dialer to place calls based upon the management of three categories of calls, namely, calls in the process of being set up, calls in a queue waiting for an available agent, and calls connected to an agent. The pacing algorithm attempts to keep the total number of these categories of calls equal to a constant value. As the size of the agent group changes, the pacing of the predictive dialer is adjusted.
U.S. Pat. No. 4,829,563 entitled xe2x80x9cMethod for Predictive Dialingxe2x80x9d, issued to Crockett et al on May 9, 1989, and describes a predictive dialing system based upon a prediction of the number of operators expected to be available at the end of a time interval and of the number of calls expected to be completed during this time interval. The predicted number of calls is then determined by a weighting factor which is controlled by variations in the percentage of unattended calls and variations in the average operator idle time between calls. The system dynamically adjusts the number of calls dialed based upon a comparison of these factors.
U.S. Pat. No. 5,155,763 issued to Bigus et al on Oct. 13, 1992 and is assigned to International Business Machines Corporation. This patent, entitled xe2x80x9cLook Ahead Method and Apparatus for Predictive Dialing Using a Neural Networkxe2x80x9d, describes a computer system connected to a telephone switch that stores a group of call records including a number of factors pertaining to previous calls and other factors; these factors include the number of pending calls, the number of available operators, the average idle time, the completion rate, and nuisance call rate. These call records are analyzed by a neural network to determine a relationship between input parameters and the dial action stored in each call record. After this relationship is determined, the computer system sends a current group of input parameters to the neural network and based on the analysis of the previous call records, the neural network determines whether a call should be initiated or not.
U.S. Pat. No. 5,327,490 issued to Ellis K. Cave on Jul. 5, 1994 and relates to a xe2x80x9cSystem and Method for Controlling Call Placement Rate for Telephone Communication Systemsxe2x80x9d. A call pacing system is described in which outbound calls are automatically paced so that an attendant becomes available as a valid call is completed. Two primary factors are determined to assess when a new call is to be dialed, consisting of how long the agent will talk, and how long and how many calls it will take to get a live answer when a call is placed. Once the call placing algorithm is aware of these two average times, it then calculates how long to wait after the agent has started talking before starting to place calls to get a connection to the next customer.
U.S. Pat. No. 5,341,412 issued to Ramot et al on Aug. 23, 1994 and is entitled xe2x80x9cApparatus and a Method for Predictive Call Dialingxe2x80x9d. This patent describes automated dialing systems using a predictive dialing system where telephone numbers are dialed under the control of one or more computers. Each agent has access to full telephone keypad functionality and a computer workstation. The system provides for optimal call scheduling with two alternative methods for responding to calls which are completed before an agent is available. The administrator can select to either terminate these calls or have a recording played until an agent becomes available.
U.S. Pat. No. 5,467,391 entitled xe2x80x9cIntegrated Intelligent Call Blendingxe2x80x9d, issued to Norman J. Donaghue et al on Nov. 14, 1995, pertains to a telephone call servicing operation in which agents can be transferred from dealing with inbound calls to outbound calls or vice versa, depending upon workload and various factors. Agents are transferred from inbound call servicing to outbound call servicing when the agent response indicator is below a predetermined threshold. In this way agent""s time is effectively utilized.
U.S. Pat. No. 5,570,419 issued to Cave et al on Oct. 29, 1996 and is directed to a xe2x80x9cSystem and Method for an Improved Predictive Dialerxe2x80x9d. A goal-based automatic call placing system is described which allows a supervisor to establish target values for particular telephone call parameters such as agent utilization, drop rate or hold time, and then adjust the length of the call pacing delay for the dialing of new calls in order to reach the target values.
U.S. Pat. No. 5,640,445 issued to John E. David on Jun. 17, 1997 and is directed to an xe2x80x9cOutbound Call Pacing Method Which Statistically Matches the Number of Calls Dialed to the Number of Available Operatorsxe2x80x9d. As the dialing process begins, the system controls the number of calls being made at any one time, based on the number of operators that are available to receive the calls and the maximum allowable abandoned call rate. A weight is assigned each agent engaged in a call or in wrap-up work, which is a function of how long an agent has been engaged in a call or in the wrap-up work, the length of adjustable time windows, and the maximum allowable abandoned call rate. The sum of these weights is a predicted number of engaged agents that will become free. This, then, is one of the factors that is used to determine the number of calls to be dialed.
Pacing processes use predictive engines to estimate how many currently busy agents may become available within a given timeframe. Most existing predictive engines including those referred to in the prior art above, such as the standard deviation based engines, predict the agent availability in terms of yes/no decisions on an agent by agent basis. These yes/no estimations are not additive and therefore have to be used by the pacing process each individually. This approach does not fit very well with the real call centre situation where the availability of the agents as a whole is more essential than the availability of each individual agent. Furthermore, yes/no decisions are very broad or coarse, where only two values are available, especially when the decisions must be made in isolation. These results are also subjective since the line between a yes/no decision can be blurred and is usually arrived at somewhat artificially. It is therefore concluded that a new approach to pacing algorithms for use in predictive dialers is required.
It is one object of the present invention to provide a new pacing algorithm for use in predictive dialers for use in call centre applications.
It is another object of the invention to provide a pacing algorithm which is based on mathematical probability models resulting in a more efficient dialing of customers along with a minimization of the attendant""s idle time.
It is a further object of the invention to provide new predictive dialer methods and apparatus embodying the pacing algorithm described herein.
According to one aspect of the invention, there is provided a call pacing method for predicting the number of active telephone call connections at a call centre that will be terminated in defined time segments within a time period, comprising the steps of creating a call time distribution array of calls consisting of the number of telephone call connections that are terminated during each of a number of equal time segments, creating an inverse cumulative call time distribution array of calls consisting of the cumulative number of telephone call connections that are yet to be terminated for each of a number of equal time segments, creating a predictive reference vector by dividing each entry of the call time distribution array with the corresponding time segment entry of the inverse cumulative call time distribution array, determining the value of the predictive reference vector of a current total active call state, and calculating the most likely number of said active telephone call connections to terminate within the period of time for each time segment using the predictive reference vector and the value of the predictive reference vector of the current total active call state.
According to another aspect of the invention there is provided apparatus for implementing a call pacing method for predicting the number of active telephone call connections at a call centre that will be terminated in defined time segments within a time period, comprising means for creating a call time distribution array of calls consisting of the number of telephone call connections that are terminated during each of a number of equal time segments, means for creating an inverse cumulative call time distribution array of calls consisting of the cumulative number of telephone call connections that are yet to be terminated for each of a number of equal time segments, means for creating a predictive reference vector by dividing each entry of the call time distribution array with the corresponding time segment entry of the inverse cumulative call time distribution array, means for determining the value of the predictive reference vector of a current total active call state, and means for calculating the most likely number of said active telephone call connections to terminate within the period of time for each time segment using the predictive reference vector and the value of the predictive reference vector of the current total active call state.